N-lower alkyl pyrrolidones have found wide commercial acceptance as non-toxic aprotic chemical solvents. N-lower alkyl pyrrolidones do not however possess significant aqueous surfactant properties. Long chain alkyl pyrrolidones such as N-dodecyl pyrrolidone are known to be surfactants with good foaming properties. N-dodecyl pyrrolidone is used for instance in the manufacture of toiletries and cosmetics. Use of such long chain alkyl pyrrolidones is however restricted due to their lack of solubility in water N-dodecyl pyrrolidone for instance is soluble in water only to the extent of about 0.1 wt. % to about 0.2 wt. %. The usual method of incorporating long chain alkyl pyrrolidones such as N-dodecyl pyrrolidone in aqueous media is to dissolve the pyrrolidone in a small volume of a water soluble organic solvent such as ethanol and then add this solution to the aqueous medium. This technique has shortcomings. The water insoluble pyrrolidone is very likely to separate out of the aqueous medium. Even if this does not happen, a quantity of organic solvent, sometimes unwanted, is necessarily introduced into the aqueous system.
Another material which is well known but is generally considered insoluble in water is chlorhexidine free base which is soluble in water only to the extent of about 0.008% -0.01% at 25.degree. C. Chlorhexidine digluconate is widely used for instance as a germicide at pH 5.5. At higher pH 8.0 the free base will precipitate out of water. Its use is frequently limited because of its limited solubility in water. It is accordingly an object of the present invention to provide aqueous solutions containing effective amounts of chlorhexidine free base and long chain alkyl lactams. Another object of the invention is to provide a method for preparing such aqueous solutions of chlorhexidine and long chain alkyl lactams.